Method of and apparatus for casting cored castings



H. W. OLSEN Nov. 14, 1961 Filed June 11, 1959 u 2 h ulz I c 2 4 \k\\\\\\ 4 2 a J I M H m m,

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bale/H21: //orace M 0/5211 United States Patent Oflflce 3,008,200 Patented Nov. 14, 1961 3,008,200 METHOD OF AND APPARATUS FOR CASTING CORED CASTINGS Horace W. Olsen, Houston, Tex. (1501 Concordia Ave., Austin 2, Tex.) Filed June 11, 1959, Ser. No. 819,770 4 Claims. (Cl. 2257) This invention relates to new and useful improvements in the art of casting castings with cored passages, and the principal object of the invention is to provide a novel method of casting such castings without the use of conventional cores of sand or other refractory material which require to be baked or cured with a suitable binder in order to provide the necessary strength for maintaining their shape, yet be capable of yielding under shrinkage of the casting material during cooling. The fabrication of such conventional cores is not only a tedious task which requires highly skilled labor, but the positioning thereof in a mold necessitates the use of reinforcing wires, et cetera, and their removal from the finished casting usually involves a considerable cleaning problem.

The present invention eliminates these difficulties by the use of a hollow, thin-walled liner which is placed in a mold cavity so as to conform substantially to the size and shape of the cored passage desired and which, after pouring of the casting material into the mold, becomes an integral part of the casting so that its removal from the casting is not necessary.

In fact, one of the important features of the invention resides in thepresence of the liner in the finished casting as an integral part thereof, inasmuch as the liner, composed ofappropriate material such as copper or brass, effectively prevents corrosion in water passages of iron castings such as those used for cylinder blocks or heads of internal combustion engines, and the like.

Another important feature of the invention resides in the provision of a fluid core which is introduced into the liner prior to pouring of the casting material and serves to structurally support the liner against collapsing, together with the provision of means for permitting the fluidcore to expand exteriorly of the liner so as to compensate for dynamic forces which act on the liner during cooling and shrinkage of the casting material.

Another important feature of the invention resides in using a fluid core composed of magnetizable particles, together with means for magnetically energizing the same so as to lock the particles together and thereby attain the required rigidity of the liner while still permitting compensation for shrinking, as aforesaid.

Anothe important feature of the invention involves the use of a coating of diifusible, refractory flux on the outer surface of the liner to delay the transfer of heat from the casting material to the liner during the initial stage of cooling, but permit diffusion of such a coating into the casting material so as to firmly bond the liner to the casting material when the latter is ultimately set.

In conjunction with the foregoing objects and features, the invention in addition to the novel method of casting also provides a novel casting apparatus.

With the foregoing more important objects and features in view and such other objects and features as may become apparent as this specification proceeds, the in vention will be understood from the following description taken in conjunction with the accompanying drawings, wherein like characters of reference are used to designate like parts, and wherein:

FIGURE 1 is a sectional view, partly in diagrammatic form, showing the apparatus for, the method of, and the resultant product in casting in accordance with the invention;

FIGURE 2, is a group perspective view showing two complemental parts or sections of the liner; and

FIGURE 3 is a fragmentary sectional view, on an enlarged scale, of the fluid core, liner, casting material and mold used in the invention.

Referring now to the accompanying drawings in detail, the reference numeral 10 generally designates a suitable conventional mold, having a cavity 11 formed therein so as to correspond substantially to the external size and shape of the casting to be cast, in the instance illustrated, a faucet valve housing, although it is to be understood that the teachings of the invention are applicable to casting of castings in general, wherever formation of cored passages in such casting is desired.

The cavity 11 is adapted to be filled with casting material through a suitable pouring hole 12 and suitable vent or riser holes 13 also communicate with the cavity 11 in accordance with conventional practice.

The invention resides in the provision of a hollow, thin-walled shell or liner 14 which is positioned in the a cavity 11 in spaced relation from the cavity walls and conforms substantially to the size and shape of the pas sage which is desired to be made in the completed casting. The liner 14 is preferably made by dies in two complemental parts or sections 14a, 14b, as shown in FIGURE 2, and the thickness of its walls need not exceed a few thousandths of an inch, so that it is rigid enough to maintain its shape in the absence of external or internal stresses, yet is yieldable under shrinkage of the casting material when the latter is poured, as will be hereinafter explained. The liner 14 is made of suitable material such as brass, copper, or the like, and the extremities thereof are elongated so that they project beyond the confines ofthe cavity 11 as indicated at 140, these projecting extremities being accommodated in the mold 10 as shown, so that they serve to retain the liner 14 against shifting within the cavity, as will be readily apparent.

The interior of the liner 14 is adapted to receive therein a fluid core 15 which serves to prevent the liner from collapsing under external pressure of the casting material, such a core preferably being in the form of relatively small, metallic spheres or particles such as iron or steel balls, which may be either solid or hollow, as desired. This core is introduced into the liner 14 by one or more pistons or plungers 16, 16a slidable in suitable chambers or cylinders 17, 17a with which the mold 10 is equipped, the size of the spheres or particles of the fluid core being sufliciently small that the core as a whole is capable of closely conforming to the configuration of the liner 14 into which it is introduced.

The mold 10 is also provided with an equalizing tube or chamber 18 into which the fluid core 15 may expand during cooling and shrinkage of the casting material, the chamber 18 communicating with the top of the cavity 11 so that the fluid core rising thereinto may exert a head pressure through itself upon the interior of the liner 14. The pistons or plungers 16, 16a are slidable manually or by mechanical means of any suitable conventional type, as desired.

In terms of its description thus far, the operation and use of the invention will be understood from the followmg:

Upon placing of the liner 14 within the cavity 11, the fluid core 15 is introduced into the liner by the piston means 16, 16a, so that it completely fills the interior of the liner as shown. Thereupon, suitable casting material is poured into the mold through the pouring hole 12 so that it fills the cavity 11 exteriorly of the liner 14 as indicated at 11a, such casting material also rising into the vent or riser holes 13, as is customary. The presence of the fluid core 15 in the liner 14 will prevent the liner from collapsing under external pressure of the casting material, but when during cooling the castingmaterial shrinks, the core 15 is sufliciently fluid as to expand and rise into the equalizing chamber 13 as shown, thus permitting the liner 14 to adjust itself under dynamic forces to the shrunk size of the cast material. Thereupon the casting operation is completed by simply withdrawing the piston means 16, 16a to permit the fluid core 15 to be removed from the casting, and by removing the casting itself from the mold in the usual manner.

During the cooling and shrinkage of the casting matevarious modifications may be resorted to, such as may lie within the spirit and scope of the appended claims.

What is claimed as new is:

l. A method of casting castings with cored passages, comprising the steps of placing a hollow thin-Walled liner into a mold so as to correspond substantially to the size and shape of the cored passages desired, introducing a fluid core material of magnetizable particles into the i liner for the liner and said material to constitute the rial 11a, the liner 14 will become an integral part therer of and of the finished casting when the-fluid core 15 is removed, thenominal thickness of the liner being virtually negligible, yet serving an important function'of protecting the cast material against damage by corrosion, or the like, when the casting is used, for example, as a cylinder block or head and the cored passage therein is filled with water of the cooling system.

In order to assist the bonding of the liner 14 to the casting material 11a, the outer surface of the liner is preferably coated with a suitable diffusive, refractory flux prior to positioning of the liner in the mold. Such a coating not only serves to delay the transfer of heat from the poured casting material to the liner during the initial stage of cooling, but, upon diffusion into the casting material, serves to firmly bond the liner to the cast material in the finished product.

In instances where gas or excessive slag is produced by the reaction of the lfllJX and the hot casting material, the size and/ or number of the vent holes 13 may be increased as required.

As already mentioned, the particles of the fluid core 15 may be metallic, but also ceramic or even liquid material may be used. In the preferred arrangement, metallic particles are used in the fluid core, of a nature capable of responding to magnetic forces in instances where it may be desirable to lock the particles together by a suitable magnetic strength for a suitable time interval during the casting process. Under such circumstances, one of the pistons, for example, the piston in, may be equipped with a magnetizable armature 1Q, energized by an electro-magnetic coil which, in turn, is actuated by a suitable source of current 21 through a switch 22. Similarly, a magnetizable armature 23, provided in the equalizing chamber 18 and energizables'by an electromagnetic coil 24 from a current source 21a through a switch 22a may be used in conjunction with the armature 19 to magnetically energize the particles of the fluid core 15 and cause them to lock or adhere to one another, thus increasing the density of the fluid core medium and the reinforcing strength which it provides for the liner 14. The switches 22, 220 may be closed either individually or jointly for the required periods of time and the strength of the electro-magnetic coils 20, 24 may be varied by suitablerheostats, or the like (not shown), so as to obtain the desired magnetic effect.

While in the foregoing there has been described and shown the preferred embodiment of the invention, various modifications may become apparent to those skilled in the art to which the invention relates. Accordingly, it is not desired to limit the invention to this disclosure and core, magnetically energizing said fluid core material whereby to lock the particles thereof together, pouring casting material into the mold exteriorly of the liner, permitting equalization of dynamic forces in the fluid core material so that the liner may adjust itself to shrinkage of the casting material during cooling and become a part of the casting, and subsequently demagnetizing said fluid core material when the casting material is set, and removing the fluid core material from the liner and the casting from the mold.

2. The method as defined in claim 1 together with the step of providing a coating of diffusible refractory flux on the outer surface of said liner prior to placing thereof into said mold, utilizing said coating to delay transfer of heat from saidcasting material to the liner during the initial stage of cooling of the casting material, and permitting said coating to ultimately diffuse into the castingmaterial and'bond the casting material and theliner together when the casting is set.

3. The method as defined in claim 1 wherein said step of permitting equalization of dynamic forces in the fluid core material includes permitting said fluid core material to expand exteriorly of said liner.

4. An apparatus for casting castings with cored passages, comprising in combination, a mold having a cavity therein corresponding substantially to the exterior size 7 and shape of the casting to be cast, a hollow thin-walled liner positioned in said mold in spaced relation from the walls of said cavity and within the latter, a fluid core material provided within said liner and therewith constituting a core, means for pouring casting material into said cavity exteriorly of the liner, means for permitting expansion of the fluid core exteriorly of the liner during cooling and shrinking of the stated casting material, a

coating of difi'usible refractory flux provided on the outer surface of said liner and adapted to diffuse into the stated casting material during cooling of the latter whereby to bond the liner and the casting material together, said fluid core material comprising magnetizable particles, and means disposed in the cavity of said mold and engaging said magnetizable particles for magnetically energizing said core and locking the particles thereof together.

References Cited in the .file. of this patent UNITED STATES PATENTS 2,170,486 Ruppik Aug. 22, 1939 2,332,330 McMahan Oct. 19, 1943. 2,438,405 Kinnear Man-23, 1948 2,517,902 Luebkeman Aug. 8, 1950 2,778,077 Andrews Jan. 252, 1957" 2,922,255 Broderick Jan. '26, 1960- 

